A gas turbine engine generally includes a fan and a core arranged in flow communication with one another. Additionally, the core of the gas turbine engine general includes, in serial flow order, a compressor section, a combustion section, a turbine section, and an exhaust section. In operation, air is provided from the fan to an inlet of the compressor section where one or more axial compressors progressively compress the air until it reaches the combustion section. Fuel is mixed with the compressed air and burned within the combustion section to provide combustion gases. The combustion gases are routed from the combustion section to the turbine section. The flow of combustion gasses through the turbine section drives the turbine section and is then routed through the exhaust section, e.g., to atmosphere.
Conventional gas turbine engines include rotor assemblies having shafts, compressor impellers, turbines, couplings, sealing packs, and other elements required for optimal operation under given operating conditions. These rotor assemblies have a mass generating a constant static force due to gravity, and also generate a dynamic force due to, e.g., imbalances in the rotor assembly during operation. Such gas turbine engines include bearing assemblies to sustain and support these forces while permitting rotation of the rotor assembly. A typical bearing assembly includes a bearing housed within a bearing housing and a bearing pad configured between the bearing and the shafts.
At least some known rotary machines use gas bearings where non-oil lubricated bearings are desired. However, for successful operation, gas bearings must address typical mission cycle loads. In most cases, the shaft movement (i.e. due to static/dynamic loads) with respect to the bearing mounting surfaces is misaligned and/or angled. Therefore, force distribution on the bearing pad is non-uniform and can lead to edge loading, which can potentially damage the bearing assembly. In an effort to mitigate edge loading effects of the bearing pad and generate better load capacity, a distributed gas delivery orifice map is required, rather than a centered pressurization system indicative of most gas bearing designs. Furthermore, the orifice map must be efficiently connected to the primary gas delivery duct in the bearing housing.
In view of the aforementioned, a bearing pad having an internal gas distribution labyrinth would be welcome in the art.